import java.util.HashMap;

// The main method must be in a class named "Main".
class Main {
    public static void main(String[] args) {
        
        HashMap<String, String> map = new HashMap<>();
        
        map.put("sunny", "blue");
        map.put("cloudy", "grey");
        
        String color;
        
        color = map.get("sunny");         
        System.out.println(color); // blue
        
        color = map.get("windy"); 
        System.out.println(color); // null
    }
}